Oxidative dyestuffs have achieved considerable importance in the area of hair dyeing. The dyeing is brought about in the hair shaft by the reaction of certain developer substances with suitable coupler substances in the presence of an oxidizing agent.
Numerous special requirements are set for oxidative dyestuffs which are used for dyeing human hair. For example, they must be unobjectionable in toxicological and dermatological respects and must enable the desired dyeing intensity. Favorable fastness to light, permanent waving, acids and rubbing are required of the achievable hair colorings. But such hair colorings must in every instance remain stable over a period of at least 4 to 6 weeks without being affected by light, rubbing or chemical agents. Moreover, it is necessary that a wide assortment of different color shades can be produced by combining suitable developer and coupler components.
1,4-diaminobenzene, 2,5-diaminotoluene, 3-methyl-4-aminophenol and p-aminophenol in particular are used as developer substances. Resorcinol, 4-chlororesorcinol, 2-methylresorcinol, 2,4-diaminoanisole, m-phenylenediamine, 1-naphthol and m-aminophenol are preferably used as coupler substances.
Resorcinol and m-aminophenol are preferably used as coupler substances in combination with p-phenylenediamine or 2,5-diaminotoluene as developer substances to achieve natural tones. In so doing, the yellow cast produced by resorcinol is compensated for by the addition of m-aminophenol so that warmer tones are obtained. The m-aminophenol is suitable for use as coupler component in oxidation hair dye compositions for producing fashionable tones, especially fashionable red tones, only under certain conditions, since it produces inadequate dyeing with respect to coloring intensity with p-aminophenol or its derivatives.
Hair dye compositions containing m-aminophenol derivatives as coupler substances are known from DE-OS 38 17 710. An example of such an aminophenol derivative is 3-amino-4-methoxyphenol. However, the latter is auto-oxidizable and, with p-phenylenediamines as developer substances, produces weak blue to violet coloring. No dyestuff is formed under the usual oxidative conditions with p-aminophenols as developer substances and 3-amino-4-methoxyphenol as coupler component.
Further, 5-amino-4-chloro-2-methylphenol, as coupler substance for oxidative hair dye compositions, is known from DE-OS 35 24 329. 5-amino-4-chloro-2-methylphenol leads to coloring in the red range whose dyeing intensity and red component are not satisfactory.